Does anyone know (from experience) if a 300 head will work on a 260 block? I believe that the valves are too large and will hit the block (and I don't want to notch the block).

After my machine shop screwed up 2 (two) heads for my 260, all I have left is a 300 head and cam, not damaged and ready for valve guides and seals.

First head: Rocker arm towers were installed in reverse order (at machine shop) from front to rear, causing the cam to lock up and break in half after 10 minutes of run-time.

Second head: was not vatted and therefore oil deposits were left inside the rocker arm tower bolt holes, and four bolts backed out, causing damage to four cam lobes and their rocker arms.. (and now I'm sick again ).....so I have a 300 head that has no pits in the cam lobes that I would love to be able to bolt onto my 260 block....without modification to the block that is.

Some say that third time is the charm....all I want to do is drive my Benz to Canada and then to Miami without fearing that the head will have issues...again. Has anyone made this operation successful?

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'87 300E | 2.6 engine
Artic White - Navy blue interior, chrome rims, very clean and sharp!
91 300E
89 300E


The rest of my collection are just cars and trucks...no more "automobiles"...

sounds like you need a better machine shop to do the head...

Alon

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'92 300CE - Sold
2004 C240 - 744 - C7 Wheels - Android Radio
2002 C320 - 816 - Sport Wagon

That's a BIG 10-4! The though crossed my mind once or twice, believe me, but now that i have all this sweat equity established with the machine shop, I'm going to deal out the hand that I have, that being credit for one last head (hopefully) or cam (non-pitted) and rockerarm towers. That's why I need to know from someone that has bolted and run a 300 head on the 260.

The bore in the 300 is slightly larger than the 300, therefore I would have to use the 300 head gasket, but if I'm not mistaken the larger 300 valves will strike the 260 block, at the top of the bore...I don't want to use any spacer or notch the block...unless someone knows that it will work....(I don't want to be the first one to do this, no matter what the result, but I believe notching is the only way, so that's out of the question, and/or I'll have to get another 260 cam with rockerarm towers. I believe the 260 and 300 share the same camshaft, just not valve size. The intake valves are larger I think.

But thanks for your thoughts Alon, I appreciate you thinking of my best interest.

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'87 300E | 2.6 engine
Artic White - Navy blue interior, chrome rims, very clean and sharp!
91 300E
89 300E


The rest of my collection are just cars and trucks...no more "automobiles"...

I'm pretty sure that the 300 E head has larger combustion chambers than the 260 E does. I'm fairly confident that it is interchangeable but the larger chambers will lower the compression of the 2.6 considerably. With lower compression you will have considerably less power, not good considering the 2.6 is already the smallest gas engine available in 124 chassis. I've always dreamed of using this setup for a turbo install. Probably would be a poor setup naturally aspirated.

actually 260 is not the smallest gas engine in w124, the stromberg carburated m102 with 2 litre displacement was the smallest and slowest gas powered w124, with only 109 hp (din) at the crankshaft.

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2001 E200 Kompressor Avantgarde
1987 300E 5-speed
1976 450SLC
1975 280S (sold)
1973 230.6 (sold)

Whoa, I would hate to see the 0 to 60 times on that one!

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2006 BMW M5 "Heidi" @ 109,000 miles
2005 MBZ C55 AMG "Lorelai" @ 165,000 miles
1991 MBZ 300E "Benzachino II" @ 165,000 miles
1990 MBZ 500SL "Shoshanna" @ 118,000 miles

(On the hunt for a good used M103 engine as of 6/10/23, PM me if you have one to sell!)